feat: add cookie consent banner for GDPR compliance

Slides up on first visit, remembers choice in localStorage.
Accept → grants analytics_storage, Decline → keeps denied.
Returning visitors get their previous choice restored silently.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app/(frontend)/[locale]/layout.tsx

@@ -7,6 +7,7 @@ import { routing } from '@/i18n/routing'
 import Nav from '@/components/layout/Nav'
 import Footer from '@/components/layout/Footer'
 import GoogleAnalytics from '@/components/analytics/GoogleAnalytics'
+import CookieConsent from '@/components/analytics/CookieConsent'
 import '@/styles/globals.css'
 
 const BASE_URL = 'https://letsbe.biz'
@@ -107,6 +108,7 @@ export default async function LocaleLayout({ children, params }: Props) {
           <Nav />
           {children}
           <Footer />
+          <CookieConsent />
         </NextIntlClientProvider>
       </body>
     </html>

src/components/analytics/CookieConsent.tsx

@@ -0,0 +1,79 @@
+'use client'
+
+import { useState, useEffect } from 'react'
+
+const CONSENT_KEY = 'cookie_consent'
+
+type ConsentState = 'granted' | 'denied'
+
+function updateConsent(state: ConsentState) {
+  if (typeof window !== 'undefined' && typeof window.gtag === 'function') {
+    window.gtag('consent', 'update', {
+      analytics_storage: state,
+    })
+  }
+}
+
+export default function CookieConsent() {
+  const [visible, setVisible] = useState(false)
+
+  useEffect(() => {
+    const stored = localStorage.getItem(CONSENT_KEY)
+    if (stored === 'granted' || stored === 'denied') {
+      // Restore previous choice
+      updateConsent(stored)
+    } else {
+      // No choice yet — show banner
+      setVisible(true)
+    }
+  }, [])
+
+  const handleAccept = () => {
+    localStorage.setItem(CONSENT_KEY, 'granted')
+    updateConsent('granted')
+    setVisible(false)
+  }
+
+  const handleDecline = () => {
+    localStorage.setItem(CONSENT_KEY, 'denied')
+    updateConsent('denied')
+    setVisible(false)
+  }
+
+  if (!visible) return null
+
+  return (
+    <div
+      role="dialog"
+      aria-label="Cookie consent"
+      style={{ animation: 'cookie-slide-up 0.5s ease-out' }}
+      className="fixed bottom-0 left-0 right-0 z-50 p-4 sm:p-6"
+    >
+      <div className="max-w-xl mx-auto rounded-2xl bg-surface-high border border-outline-variant/20 shadow-[0_-4px_32px_rgba(25,28,29,0.12)] p-5 sm:p-6">
+        <div className="flex flex-col sm:flex-row sm:items-center gap-4">
+          <p className="text-sm text-outline leading-relaxed flex-1">
+            We use cookies to understand how visitors use our site.
+            No personal data is shared with third parties.
+          </p>
+          <div className="flex items-center gap-2.5 flex-shrink-0">
+            <button
+              type="button"
+              onClick={handleDecline}
+              className="px-4 py-2 rounded-xl text-sm font-medium text-outline transition-colors hover:bg-on-surface/5 cursor-pointer"
+            >
+              Decline
+            </button>
+            <button
+              type="button"
+              onClick={handleAccept}
+              className="px-5 py-2 rounded-xl text-sm font-medium text-white transition-all hover:-translate-y-px active:translate-y-0 cursor-pointer shadow-[0_4px_16px_rgba(0,100,148,0.25)]"
+              style={{ background: 'linear-gradient(135deg, #006494, #5BA4D9)' }}
+            >
+              Accept
+            </button>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}

src/styles/globals.css

@@ -91,6 +91,11 @@
   87.5%  { transform: translate(-120px, 120px); }
   100%   { transform: translate(0px, 170px); }
 }
+@keyframes cookie-slide-up {
+  from { transform: translateY(100%); opacity: 0; }
+  to   { transform: translateY(0); opacity: 1; }
+}
+
 @keyframes hero-orbit-b {
   0%     { transform: translate(0px, -130px); }
   12.5%  { transform: translate(-90px, -90px); }